The present invention relates to information and display systems or terminals and, specifically, relates to portable terminals having visual displays and keyboards contained within a package easily transportable by a single person.
Technological advances in the computer industry and in computer related instruments have caused the overall size of many computing systems to be decreased drastically. Indeed, the fact that the computers can be of such a small size has added much to their marketability. Along with the reduction in size of the computer has also come the proliferation of small "terminals". The overall dimensions of such small terminals have also been reduced substantially and now are generally desk-top size. These so-called "portable" terminals typically employ a cathode ray tube (CRT), a keyboard, one or more disc drives for accepting the software that permits the terminal to emulate the system with which it communicates, and a relatively small amount of local storage.
There are presently two main kinds of CRT terminals, one of which runs on or "talks to" IBM mainframe computers, such as the IBM 360/370 and 3000/4300 series. These are known as 3270 terminals. The second kind of CRT terminals run on or talk to mainframe computers or minicomputers made by other manufacturers. This second kind of terminal is generally referred to as an ASCII terminal, which is an acronym for American Standard Code for Information Interchange.
The CRT terminal is typically used in combination with the appropriate software, via the disc drive, to permit the terminal to emulate the specific host computer. This emulation is based upon the particular protocol used by the computer. Integral with this protocol compatibility is the data communication methodology that is employed. The original data communications protocol used by the 3270 terminals is known as binary synchronous communications (BSC) or bisynch. A more recent IBM data communication methodology is known as Systems Network Architecture/Synchronous Data Link Control (SNA/SDLC). Therefore, the terminal selected by the user must be compatible with the data communication methodology of the main computer. In that regard, there are now available devices known as "protocol convertors" to meet either the bisynch or SNA/SDLC standard. Thus, many present terminals are actually user-programmed microcomputers requiring a controller to meet the various protocols.
The trend then in this kind of computer support equipment is toward more and more compatibility in these terminals and, along with this, go increases in system complexity, cost, and size. While being loosely referred to as "portable", these presently available terminals have gotten heavier and more difficult to transport and, in all events, are not portable in the sense that they may be easily transported from one location to another by a single person, e.g., by public transportation, such as being placed under an airline seat.